Strong paper from spruce CTMP – Part II: Effect of pressing at nip press temperatures above the lignin softening temperature

Norgren, Sven; Pettersson, Gunilla; Höglund, Hans

doi:10.1515/npprj-2018-3009

Cited by 14 publications

(19 citation statements)

References 8 publications

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“…Interesting is that density for the HYP based samples show almost the same value, only about 10% lower, as for the NSK based samples when pressed at 200°C. This was previously verified by Norgren and Pettersson at FSCN/Mid Sweden University (Norgren et al 2018;Pettersson et al 2017). The increase in density was about 100% for HT-CTMP, 50% for CTMP and 75% for TMP.…”

Section: The Effect Of Pressing Load and Temperature On Paper Propertiessupporting

confidence: 74%

“…This makes the HYP containing stiff fibres most suitable for press-drying. Press-drying of HYP at high temperature has been further studied by Pettersson et al andNorgren et al in 2017 and2018, and they confirm the development of strength properties due to densification and increased bonded area in the paper structure (Norgren et al 2018;Pettersson et al 2017). However, in the 1980s (Back, Andersson 1979;Back 1984;Back, Olsson 1989;Swensson 1987) investigated heat treatment and dry pressing of unbleached chemical kraft paper products, particularly linerboard with the aim to improve both dry and wet strength properties.…”

Section: Hot-pressing Since the 1920smentioning

confidence: 95%

“…with the Impulse drying technique and developments in press-drying technology by Back in the 1980s (Back 1984;Wahren 1982). Further investigations about the impact of pressing and warm-pressing on HYP and chemical pulp have sparingly been done during recent years (Klinga et al 2007b;Lucisano 2002;Norgren et al 2018;Pettersson et al 2017).…”

Section: Hot-pressing Since the 1920smentioning

confidence: 99%

“…This can be explained by a probably higher dry content in the second nip since the paper sheet is certainly dried in the first nip. High enough moisture content in paper sheets is a prerequisite to soften the lignin and hemicellulose in the fibre walls and between the fibres (Back, Andersson 1979;Norgren et al 2018;Pettersson et al 2017).…”

Section: Development Of Wet Strengthmentioning

confidence: 99%

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High strength paper from high yield pulps by means of hot-pressing

Joelsson

Pettersson

Norgren

et al. 2020

Nordic Pulp &Amp; Paper Research Journal

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AbstractThe hypothesis is that it should be possible to modify papermaking conditions in line with the softening properties of high yield pulp fibres and achieve similar strength properties to conventional chemical pulp based paper. We therefore investigated the rheological and physical properties of high yield pulp based papers during hot-pressing. Our results confirm that increased temperature combined with sufficient pressure enables permanent densification by softening of lignin, producing very high tensile strength. This treatment also significantly improved the wet tensile strength in comparison to bleached kraft pulp without using wet strength agents. The high yield pulps used here were spruce based thermomechanical pulp, chemi-thermomechanical pulp, and high temperature chemi-thermomechanical pulp, and birch-aspen based neutral sulphite semi chemical pulp, with spruce-pine based bleached kraft pulp as reference. Rapid Köhten sheets of 150\hspace{0.1667em}\text{g}/{\text{m}^{2}} and 50 % dryness were hot-pressed in a cylinder-press at 20–200 °C, 7 MPa, and 1 m/min. The mechanical properties showed great improvements in these high yield pulp papers, with tensile index increased to 75 kNm/kg and compression strength index to 45 kNm/kg; levels close to and better than bleached kraft. Wet strength increased to 16 Nm/g compared to 5 Nm/g for bleached kraft.

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Section: The Effect Of Pressing Load and Temperature On Paper Propertiessupporting

confidence: 74%

Section: Hot-pressing Since the 1920smentioning

confidence: 95%

Section: Hot-pressing Since the 1920smentioning

confidence: 99%

Section: Development Of Wet Strengthmentioning

confidence: 99%

See 2 more Smart Citations

High strength paper from high yield pulps by means of hot-pressing

Joelsson

Pettersson

Norgren

et al. 2020

Nordic Pulp &Amp; Paper Research Journal

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“…A higher mould B temperature improves the MPP's Young's Modulus for both initial and after water sorption. Several studies [23,24,27] observed that a higher processing temperature allows the tensile index to be improved as it allows to have a lower WTR and swelling capacity [21,24,30].…”

Section: Mechanical Properties Depending On the Process Parametersmentioning

confidence: 99%

The impact of molded pulp product process on the mechanical properties of molded BCTMP

Dislaire¹,

Grohens²,

Seantier³

et al. 2020

Preprint

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This study was carried out using bleached softwood Chemi-Thermo-Mechanical Pulp to evaluate the influence of Molded Pulp Products’ manufacturing process parameters on the finished products’ mechanical and hygroscopic properties. A Taguchi table was done to make 8 tests with specific process parameters such as moulds temperature, pulping time, drying time and pressing time. The results of these tests were used to obtain an optimized manufacturing process with improved mechanical properties and a lower water uptake after sorption analysis and water immersion. The optimized process parameters allowed us to improve the Young’ Modulus after 1h immersion of 58% and a water uptake reduction of 78% with the first 8 tests done.

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Unique steel belt press technology for high strength papers from high yield pulp

et al. 2021

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The dry strength properties of hot-pressed moist paper improved as stiff high-yield pulp fibers soften and the sheet density increased. Very high wet strength was also achieved without adding strengthening agents. This research focuses on a new hot-pressing methodology based on a steel belt-based pilot cylinder press with infrared heating. The heated steel belt transports the moist paper into the cylinder nip with two adjacent steel rollers with adjustable nip pressure. The temperature ranges up to 300 °C, maximum speed is 5 m/min, maximum pulling force from the steel belt is 70 kN and the line load in the two press nips is 15 kN/m each. High peak pressures are possible due to the hard press nip between steel rolls and steel belt, allowing a good heat transfer to the paper. The long dwell time allows strained drying of the paper which results to high density and high wet strength. Paper samples from high-yield pulps were tested at different nip pressures, temperatures and machine speeds while the dry content was kept constant at about 63%. High nip pressure showed the largest effect on densification and dry strength. While high temperature and long dwell time seem to be most important in achieving high wet strength.

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Strong paper from spruce CTMP – Part II: Effect of pressing at nip press temperatures above the lignin softening temperature

Cited by 14 publications

References 8 publications

High strength paper from high yield pulps by means of hot-pressing

High strength paper from high yield pulps by means of hot-pressing

The impact of molded pulp product process on the mechanical properties of molded BCTMP

Unique steel belt press technology for high strength papers from high yield pulp

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